ORIGIN OF LIFE

1. ORIGIN OF LIFE AbhijitBhattacharjee Asst Professor, Dept of Botany Swami Vivekananda Mahavidyalaya Mohanpur, West Tripura Email id: svm.mnp@gmail.com Website: svmmohanpur.nic.in

2. Origin of Earth? • The earth is said to have come into existence 5 billion years ago and before the existence of life.

3. What is Life? • Life on earth came into existence only a billion years after the existence of earth • Life is an urge of the Universe to understand itself • Life is a pageant that passes very quickly, going hastily from one darkness to another darkness with only ignes fatui to guide; and there is no sense in it. I learned that, Kerin, without moiling over books (according to James Branch Cabell). • There are two major forms of life in earth i.e. plants and animals

4. Origin of life? • It is one of the great mysteries in the Universe • The origin of life is a long-standing and controversial topic. • During the mid-17th century the British physiologist William Harvey, in the course of his studies on the reproduction and development of the king’s deer, discovered that every animal comes from an egg (a single cell). • The earliest known vascular plants come from the Silurian period. Cooksonia is often regarded as the earliest known fossil of a vascular land plant, and dates from just 425 million years ago in the late Early Silurian. 

5. Hypothetical view of origin... • The origin of life is a result of a supernatural event—that is, one irretrievably beyond the descriptive powers of physics, chemistry and other science. • Life, particularly simple forms, spontaneously and readily arises from nonliving matter in short periods of time, today as in the past. • Life is coeternal with matter and has no beginning; life arrived on Earth at the time of Earth’s origin or shortly thereafter. • Life arose on the early Earth by a series of progressive chemical reactions. Such reactions may have been likely or may have required one or more highly improbable chemical events.

6. Plant cells • plants are mainly multicellular living organ • plant cells are eukaryotic type with true nucleus • plant cells are differentiated from the cells of other organisms by their cell walls, chloroplasts, and central vacuole. • specifically, plant cells are photo-autotrophic because they use light energy from the sun to produce glucose. • Source: micro.magnet.fsu.edu

7. Major components of plant cell • cell wall • cell membrane • Nucleus • Plastids • Leucoplasts • Chloroplasts • Central Vacuole • Golgi Apparatus • Ribosomes • Mitochondria • Lysosome

8. Types of plant cells • Collenchyma Cells • Sclerenchyma Cells • Parenchyma Cells • Xylem Cells • Phloem Cells

9. Animal cells • Animal cells are the basic unit of life in organisms of the kingdomAnimalia. • They are eukaryotic cells. • unlike plants and fungi cells, do not have a cell wall. • like all eukaryotic cells, animal cells have mitochondria to create ATP. • Source: withcarbon.com

10. Organelles of animal cell • cell membrane • nucleus • ribosomes • endoplasmic reticulum • vesicles • golgi apparatus • mitochondria • cytosol • lysosome • peroxisome • Source: biologywise.com

11. Functions • Cells are highly specialized to carry out specific tasks. • Provide Structure and Support: every organism is made of cells. • Facilitate Growth through Mitosis and give rise to new organisms. • Allow Passive and Active Transport • Produce Energy • Create Metabolic Reactions • Aids in Reproduction

12. Difference between plant and animal cells

13. Source: thoughtco.com

14. References: • https://www.khanacademy.org/science/biology/history-of-life-on-earth/history-life-on-earth/v/origins-of-life • https://www.youtube.com/watch?v=xyhZcEY5PCQ • https://www.khanacademy.org/science/high-school-biology/hs-cells/hs-plant-vs-animal-cells/v/overview-of-animal-and-plant-cells • https://www.youtube.com/watch?v=H49P4meYyos